Propeller



1'. A. DICKS July 28, 1931. I

PROPELLER Original Filed June 13, 1928 2 Sheets-Sheet 2 Patented July 28, 1931 UNITED. STATES PATENT OFFICE THOMAS A. nroxs, or PITTSBURGH, PENNSYLVANIA, A'SsIeNoB. To PITTSBURGH SCREW AND BoLT CORPORATION, or PITTSBURGH, PENNSYLVANIA, a coarom- TION OF PENNSYLVANIA PBOPE'LLBR Refile for abandoned application Serial No. 285,087, filed June 18, 1928. This application filed August i 23, 1929. Serial No. 387,899.

tachably and adj ustably secured in a hub construction.

Numerous attempts have been made to Pro duce aconstruction of this general type by using interlocking shoulders and abutments, or in some instances by providing a thread- .ed connection between the adjacent ends of the propeller blade and the hub, but in' all of such cases, extreme care and" expert workmanship must be exercised to provide. a proper fit between theseveral parts. This necessarily entails high expense and adds materially to the ultimate cost of the propeller.

It has also been found that propeller blades using such types of connections are difficult to set to the proper pitch which is absolutely necessary to avoid uneven pull of the blades, wobbling of the propeller during its opera- 2'5'tion, vibration and etc., all of which tend to rob the air craft of its highest motive force. Then again the interlocking shoulders and abutments or the threaded connections have been found to so tightly bind or set, due to 0 the extremely high centrifugal action of the blades, that it'is with difliculty that the blades may be detached when such is desired.

The principal object of the present invention resides in the novel manner of providing a detachable connection between the hub and the blade of the propeller which obviates all.

complex locking connections between the propeller blade and the hub.

Another object of the invention is the provision of a simple telescopic form of joint between the blade and the hub which joint is firmly retained by the use of a cross bolt or 1n. v A further object of'tlie invention resides in the novel manner of reinforcing or strengthening the walls of the hub and the propeller blade at the point where the connection is to be made.

A still further object of the invention re- 50 sides in the yieldability of the wall of the tightened or secured.

socket arranged on the hub section so as to enable a clampingor gripping efi'ect to be had when the cross bolt or pin is properly With these and other objects in View, as will readily present themselves to those skilled in this. art, I will now proceed with the detailed description of the invention.

ber may be increased to any desired extent verse axial sleeve 6 into which a drive shaft is adapted to be secured in any appropriate.

or well-known manner. Integrally formed on the hub section 5 are socket members 7. Each 'of the sockets is provided with a relatively thickened portion adjacent its point of connection to the hub 5 as designated by the reference character 8 and a relatively reduced portion 9 which extends to the outer end of the socket. The socket 7 is longitudinally slit at its outer end as at 10 and provided with outwardly extending ears 11. The ears 11 are suitably apertured for the re ception of a bolt 12. The thickened portion 8 of the socket 7 is longitudinally cut or slit asshown at 13 for a purpose which will be hereinafter described.

Arranged within each socket' 7 and integrally formed with the hub portion 5 is a I,

instance is of tubular construction and its inner end is'ada ted to be inserted within the socket 7 on the ub portion 5. Adjacent the inner end the propeller blades are'suitably apertured as designated by the character 17 to permit the passage of the cross bolt 16. In order to reinforce the relatively thin wall of the tubular propeller blade at the point at which it is apertured, metallic blocks or inserfs 18 are used. These blocks are suitably retained in their desired position by any of the well-known means of fastening one metallic member to another, but I preferably form this connection by welding as suggested at 19. The extreme inner end of the tubular propeller blade may be upset or inwardly anged as at 20 which eflectively forms a stop or shoulder against which the end of the metallic insert or reinforce 18 may rest. This flange 20 also materially strengthens the tubular end of the blade.

In the resent case, I have shown the cross bolt or pm of angular formation, but it is of course, understood that other types of cross keys may be employed if desired. One end of this cross key 16 is provided with an arcuate head 21 which is adapted to fit snugly against the outer peripheral wall of the socket portion 7. The opposite end of the cross bolt is threaded as at 22 for the reception of a nut 23. The cross bolt as well'as the nut may be provided with apertures for the reception of a cotter pin or any other suitable type of fastening to firmly retain the nut in its tightly adjusted position. In the present case, I also preferably employ a washer 24, the inner face of which is curved to fit snugly against the outer wall of the hub portion 7 while its outer face is flattened and against which the nut 23 is adapted to ar. The key apertures 17 through the tubular wall or root of the blade portion are slightly elongated as clearly shown in Fig. 2, this being for the urpose of permittin angular ad'ustment of the blade within the socket be ore said blade is finally clamped in position. This angular ad'ustment of the individual blades enables t e mechanic to properly balance the propeller so that each individual blade will do its proportionate amount of work and without causing any vibration which would ultimately be carried to the drive shaft of the engine.

Upon insertion of the tubular end of the propeller blade, the various apertures are rought into registration and the cross bolt inserted therethrough. The individual propeller blades are then properly adjusted in regards to angle or pitch and are then tightly held in clamped position through the action of the cross key 16 and its associated nut 23.

The cross bolt 12, positioned in the outer end I of the socket, closes the latter so that it grips the tubular blade, and further reinforces t e positioning of the blade. This latter action will tightly draw the inner portion of the socket around the inner end of the inserted tubular blade and during this action the walls of the thickened portion will yield slightly owing to the longitudinal slit 13.

The internally arranged boss 14 has been found 'to strengthen the cross connection effectively by medially supporting the cross bolt. This construction prevents any possible outward bend or twist upon the pin during the action of the propeller. It will of course be understood that during the revolution of airplane propellers the blades are subjected to a terrific centri u al, bending, and twisting force. To strengt en the propeller blades against these forces, an intermediate form of support has been provided at their point of cross connection to the hub socket. I

When it is desired to repl ce any of the blades in case of damage, all that is necessary is to release and withdraw the cross pin and secondly, to loosen the cross bolt 12 in its bind or. grip of the outer end of the socket upon the inserted blade. lVith the release of said parts the blade may be easily removed by simply withdrawing the same from its socket.

While I have described in the foregoing, the preferred form of my invention, I wish it understood that certain departures therefrom may be resorted to so long as the structure falls within the terms of the appended claims.

'What I claim as new and desire to secure by Letters Patent is:

1. In a propeller, a hub having a series of sockets radiating therefrom, a hollow detachable blade having a cylindrical shank adapted to fit within each socket, each socket inserted therein being provided with suitable openings for the reception of a cross bolt and an apertured boss arranged within each socket over which the end of the blade is positioned and through which the cross bolt extends;

3. In a propeller, a hub having a series of sockets radiating therefrom, a hollowdetachable blade having a cylindrical shank adapted to fit within each socket, each socket and the end of the blade inserted therein being provided with suitable openings for the reception "of a cross bolt, the openings in the end of the blade being elongated to permit angular adjustment of the blade within its socket and means projecting from the bottom of each socket into the shank of the blade for medially embracing the cross bolt.

4. In a propeller, ahub having a series of cylindrical bosses radiating from the outer surface thereof, a socket surrounding each boss, a hollow detachable blade ada ted to fit within each socket and to surroun the boss therein, the socket, the inserted end of the blade and the boss beingJ provided with registering openings and a olt passing through said opemngs to retain the b ade in position.

5. In a hub for a propeller having a series of sockets radiatin therefrom, a detachable blade adapted to t within each socket, the inner portion of each socket being ieldable under clampin action to tightly em race the inserted end. 0 the blade and the outer portion of each socket being longitudinally split and provided with means to tightly clamp it about the shank of v the inserted blade.

6. In a propeller, a hub having a series of integrally formed bosses protruding from the outer surface thereof, and an integrally formed socket surrounding each of said bosses, a hollow detachable blade adapted v to fit within each socket and to surround the boss, the inserted end of the blade, the sleeve and the boss being provided with registering openings and a olt passing throught the openings to lock the blade in position.

7, In a propeller, a hub having a series of integrally formed bosses thereon with a socket surrounding each boss, a hollow blade adapted to fit within the socket and over said boss in spaced relation thereto and means passing throu h suitable apertures in the socket, the blade and the boss to detachably retain the blade in its inserted position.

8. The combination with a propeller having a hub, of a plurality of integrally formed radially extending socket members, cylindrical bosses within said socket members,.a plurality of detachable propeller blades, each blade having a hollow root adapted to fit within-each socket member and over each boss for rotative adjustment thereon, and common means passing through registered openings in each socket member, blade root, and. boss so that said blade can be rigidly secured to said hub.

9:" The combination with a pro 'from, an integrally forme bers, a plurality of detachable propeller blades, each blade having a hollow root adapted to fit within one of said socket members and over the boss therein, each blade root being inwardly flanged and adapted to form a stop for a reinforcing insert located therewithin, each socket member, blade root, reinforcing inserts, and boss being provided with registering openings for receiving a common bolt, the openings in each blade root and reinforcin inserts being circumferentially elongate so that the propeller blades may be ad ustabIy secured to said hub.

11. The combination with a propeller blade provided with a hub, of a plurality of integrally formed radially extendin socket members and bosses within said soc et members, a plurality of detachable propeller blades, each blade having a hollow root adapted to fit within one of said socket members and over the boss therein, the socket members, blade roots, and bosses. being'provided with registering opening for receivin common securlng means, theputer'portion 0% each socket member being longitudinally split and provided with means for obtaining a tight clamping fit between each socket member and the shank of each inserted blade, the

inner portion of each socket member being reinforced and rovided with radial slits.

12. In a hub or a propeller having a plurality of sockets extendin radially thereboss projecting from the bottom of each socket, a propeller blade having a hollow shank adapted to fit within each of said sockets and surround said boss, a cross bolt extending through openin in the socket blade shank and a boss for loc ing the blade against longitudinal movement,

means for securely clamping the outer end of the socket around said blade and means for "permltting the inner and outer portions of the socket to be yieldable under clamping action. 1

13. In a hub for a propeller having a series of sockets radiating therefrom, a boss projecting from the bottom of each socket, and a hollow detachable blade adapted to fit within each socket and surround said boss, the inner portion of said socket being yieldableunder a clamping action to tightly embrace the inserted end of the blade and the outer portion of each socket being longitudinally splitand provided with means to t1 htly clamp it about I the shank of the inserted lade. I

14. In a hub for a propeller having a series of sockets radiating therefrom, a boss projecting from the bottom of each socket, and a hollow detachable blade adapted to fit within each socket and to surround said boss, the inner portion of each socket having a radial slit for permitting said socket to yield under a clamping action so as to tightly embrace the inserted end of the blade, and the outer portion of each socket being longitudinally split and provided with clamping means on opposite sides of said split for securely fastenlng the socket about the shank of the inserted blade.

15. A propeller blade having a hollow shank provided with an inwardly extending flange on the bottom thereof and reinforcing inserts supported on said flange.

16. A detachable ropeller blade having a hollow shank provi ed with o ning for securing said blade to a propeller ub, reinforcing inserts in said shank around said open-. mgs, and an inwardly extending flange on' the lower end of said shank for supporting said inserts.

In testimony whereof, I have hereunto subscribed my name this 21st day of August,

THOMAS A. D-ICKS. 

